Family Learns Health Secrets Through Genome Sequencing

A few years ago, John West suffered two frightening pulmonary embolisms from blood clots that traveled from his leg to his lung. Up to 600,000 Americans suffer from venous thromboembolism each year, a combination of deep vein thrombosis (DVT) and pulmonary embolism (PE), and one third of them die as a result. West manages his condition with drug therapy to help prevent clots from forming.

As a former head of a genome sequencing startup company, West had a keen interest to find out if his two children would inherit his condition, which was traced to a genetic mutation called Factor V Leiden, and if so, how they could best manage their future health. West and his wife, both in their early 50s, enlisted the help of researchers at Stanford University to analyze the secrets hiding in their family’s collective 24 billion base pairs of DNA.

The West family is now the first family in the world to have their entire genomes sequenced. The findings were recently published in the journal PLoS Genetics. John West was a co-author of the study.

“The real breakthrough here was to take a family and look at the flow through their whole genetic information, to make our best estimate for their risk for disease, what drugs would work well for them in the future and which would not. For the children, we could see which piece of DNA came from Mom and which came from Dad,” says Euan Ashley, MD, PhD, lead researcher and co-author of the study. Dr. Ashley is Director of the Stanford University Center for Inherited Cardiovascular Disease.

The Stanford team found that the teenage daughter does carry the risk factors for developing dangerous blood clots, inheriting the genetic risk from her father as well as an additional factor from her mother. As a result, she is already making lifestyle changes, such as getting up and walking around if she goes on a long flight, because sitting for long periods of time is a known risk factor for those with the tendency to develop DVT/PE. The teenage son on the other hand, did not inherit the genetic risk for this condition from either parent.

Even more surprising, by running the daughter’s genome data against the Pharmacogenomics Knowledge Base, a database of known associations between gene variants and 141 drugs, the researchers were able to identify that the daughter has an increased risk of bleeding if she is prescribed an antiplatelet drug called clopidogrel in the future. Analysis also showed that the mother has an increased risk of bleeding if prescribed clopidogrel. For West himself, the research confirmed the optimal dose of warfarin to treat his condition, based on his genetic information.

The cost to sequence an entire genome has declined significantly in a short period of time. In 2001 with the advent of the Human Genome Project, the cost was several hundred million dollars to sequence an individual genome, and as of 2008 the cost was about $2 million. The West family paid $40,000 per genome in 2009 and since then, the cost has plummeted to about $4,000 per genome today. Researchers used to analyze a single molecule level at a time, but now they can sequence millions or billions of DNA molecules at once.”

Dr. Ashley sees whole genome sequencing as an exciting new frontier for the future of personal healthcare. He says, “I think everyone will have this done ultimately. Your genome will be in your medical record and this will be something your physician looks up when prescribing a new agent. That’s the dream of personal medicine.”

What secrets are hiding in your family’s genome? Would you like to know what the future holds for your family’s health or which drugs could work best or should be avoided?

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